The present invention is related to a method for starting up a wind energy plant after an operation stoppage, and a wind energy plant which can execute the method.
Wind energy plants have a drive train for the transmission of the torque of a rotor of the wind energy plant driven by the wind to a generator which provides electric energy. In the most frequent construction, the generator is operated at a rotational speed which is substantially higher than that of the rotor, so that a step-down gearbox is needed in the drive train. Such gearboxes are normally realised with two or three steps and have a number of gearings in engagement with each other. All the components of such a drive train are exposed to high mechanical strains, the gearings of the gearbox in particular are strongly strained by the high torques of the rotor. As a consequence, in spite of the intense efforts of the manufacturers of wind energy plants and gearboxes, respectively, damages in the drive train region occur always again, which can lead to the breakdown of the wind energy plant. The high strains lead also to a limited lifetime of individual drive train components, which can make a replacement of the components necessary, as the case may be. Such a replacement is accompanied by a high expense of money and time and leads to an unwanted failure of the wind energy plant.
Based on this, it is the objective of the present invention to indicate a method which permits a particularly gentle operation of the drive train components of a wind energy plant and which promotes a long lifetime of the drive train components, as well as a wind energy plant which can execute the method.